Crystal detector



"May 12, 1925. l I 1,531,856

F. MlcHELS ETAL CRYSTAL DETECTOR Filed Sept. 16, 1922 20 22 ff f5 1J f5 15 wlmmm Patented May 12, 1925.

UNITED STATES PATENT OFFICE.

j FREDERICK MroHELs AND ADOIPH ERISMAN, or NEW YORK, N. Y.

y CRYSTAL Application filed September To all whom t may concern.'

Be it known that We, FREDERrGK MICHELS and ADoLrH ERISMAN, both citizens of the United States, and residents of New York city, county and State of New York, have inventedvcertain new and useful Improvements in Crystal Detectors, of which the l the conducting wire or cat Whisker is permanently located upon the most sensitive point of the exposed face of the galena, silicon or -other crystal material. One of the prominentcharacteristics of our instrument resides in the fact that the several parts are so constructed and assembled that notwith- Lstanding severe shocks or jars incident to accident or abuse, the conducting element will not be dislodged or moved from the 'sensitive spot on the crystal face.

In a preferred embodiment of the invention, we construct the device in the form of a cartridge which is adapted for removable engagement in a holder or adaptor connected in the line circuit so that the said cartridge can be easily removed, and a new cartridge inserted therein. Thus the maximum efficiency in detection is obtained by simply attachingy the device to the radio set.

It is another object of our invention to provide a fixed crystal detector in which the surface ofthe crystal is protectedA against the accumulation of dust particles thereon which would interfere with the sensitive- 4o ness of the device.

. With the above and other objects inview,

the invention resides in the improved form,

n construction and relative arrangement Iof the several parts as will be hereinafter more fully described, illustrated in theI accompa` nying drawings and subsequently incorporated in the subjoined claims. j

In the drawing wherein we have disclosed one desirable and practical embodiment. of

' the invention and in which similar reference ,characters designate corresponding parts throughout the several views,

Figure 1 isa perspective view showing DETECTOR.

16, 19.22. -Serial N0. 588,539.

i These clips are respectivelyconnected on the under side of the base by means of wires with the binding post 7 to which the line circuit wires of the radio set 'are adapted to be connected. The opposed side portions of' each clip 6 is provided at one of its edgeswith aninwardly projecting lug 8. These lugs prevent longitudinal shifting move'- nlrent of the detector cartridge in the holding c i s.

n the form of our invention which we have selected as best illustrating the struc- I5 d tural features thereof, the body ofthe cartridge consists of a cylindrical tube 9 lof non-conducting material. This tube at one of its ends is counterbored as at 10, to receive the reduced portion 11 of a metal block 80 or crystal holder 12. In this reduced portion of the holder, the galenaor silicon 13 ismolded and projects from the face thereof. 3After the crystal holder has been inserted in the end`of the cartridge body, one end of the conducting wire4 or cat Whisker 14 is engaged with the -face of the crystal. This wire has a coil portion 15 closely 'engaged upon one end of a rod 16. The cartridge body is arranged in a, vertical position with the metal block 12 resting upon a suitable support and the rod 16 is manipulated until, the free end of the wire 14 lis, engaged upon the most sensitive spot on the crystal face.

This maybe readily determined by making suitable tests. After properly adjusting the'f'wire 14 on the crystal, a Vsuitable nonconducting materialin powdered-or` comminuted form, as shown at'l', .is 'oured into the rtubular body 9 so thatit wil) closely upon the crystal face and around the end portion of the wire 14 projecting fromthe rod 16. This rod for a portion of its lengthis'formed with threads 18 so that when the non-'conducting material 19 such 105 as wax or other composltionin Huid form poured linto thecartridge body 9, it will Vcollect in the threads 18 and around the rod to each other so that the conductingwire 14 cannot shift on the rod 16. `At the same time, it will be observed that the end portion of the wire projecting beyond said rod is held against any movement relative to the crystal by the closely packed non-conducting material 17.

Over the ends of the tubular body 9, metal caps 20 and 21 respectively, are engaged and are permanently secured thereon by a4 coating or ilm of shellac indi-cated at 22, applied to the ends of the cartridge body. However, itis apparent that other means might be utilized for fixing the metal caps in position. Between the end wall of the cap 20 and thek crystal holder' block 12, a

wire spring 23 is arranged and a smaller Vshown in Fi ends thereof eing engaged in the respective spring 24 is engaged upon .the threaded end of the rod 16 and bears against the end wall of the other cap 21. These springs 23 and 424 merely act as conductors to electrically connect the crystal and the rod 16 with the respective metal caps. e p

In ,the use of our device, it is merelyn'ecf essary to insert the cartridge in the adapter re 1, the metal caps at the springclips 6 whereby the circuit is closed. No further adjustment of any kind is reuired and in the operation of the radio set t e highest de ree 'of sensitiyeness is 0btained. 'It has that owing to Aour construction of the cartridge and the manner of assembling the several parts as above explained, t e device willY withstand very rough han ling' or abuse and even after being repeatedly dropped will possess its original responsivenes s, thus indicating that no displacement of the conducting wire from the sensitive spot on theycrystal face had occurred. It

sometimes happens, however, that due to staticlor-other natural forces, the sensitiveness of the detector `is destroyed. In such cases it is merely neceary -to, detach the cartridge from theclips 6 and insert a new cartridge in'its place. l

From the foregoing, it will` be appreciiited that we have devised a very simply constructed and inexpensive crystalI detector for use in connection with radio signalving apparatus and.one which is also lf:

rugged and substantial'wconstruction. We have herein'referred to a@ particular form and relative arrangement of the several ele- -ments comprising'the device, but it is evident that in practice it might be found desirable to make numerous alterations therein. Accordingly, it is to be understoodv that the invention may be embodied in numereen determined in practiceous other alternative construct-ions and, we therefore, reserve the privilege of resorting to all such legitimate changes as maybe fairly incorporated within the spirit and scope of the appended claims.

We claimt 1. A crystal detector for radio apparatus comprising a tubular body, a crystal holder extending into one. end of said body, an insulated conductor extending through said body, a crystal in said holder, a fiexible conducting element connected-to said insulated conductor and engaged'at. one of its ends upon the face o f the crystal, a comlninuted non-conducting material surrounding the crystal and said flexible conductingelement to prevent displacement of the latter, and circuit closing contact memsaid conductor` wire to prevent displace-4 ment of the latter, means for fixing the conductor rod against movement relative to the tubular body, and metal contact caps permanently secured upon opposite ends of said body and closing the same and connected respectively with lthe contact rod and said crystal holder.

3. As a' new article of manufacture, a crystal detector for radio apparatus in the form of a cartridge for detachable enga ement in an adaptor connected in the ra io line circuit, said cartridge consisting' of a tubularO body of non-conducting material, a detector crystal enclosed within one end of said body, conducting means extending through the body and including a coiled .exiblh wire engaged with the sensitive point of the crystal, av comminuted insulating material confining said wire against movement relative to the crystal and metal caps permanently closing the op osite ends of the cartridge body connected) with the crystal and the conducting means respectively and constituting circuit closing contacts.

4. The method of permanently fixing a cat Whisker upon vthe most sensitive point of a radio detector crystal, which consistsv in mountin the crystalwithin one end of a tubular ody, then positioning the end of the cat Whisker upon the sensitive' point of the crystal face and connecting. said cat i Whisker with a conductor, then dry comminuted insulating material wit in ackm a :A

said body against the crystal face and around the end of the cat Whisker to hold the latter against displacement from the sensitive point on the crystal face, and finally anchoring the cat Whisker and the conductor Within said tubular body and against bodily movement relative to each other.

5. The method of permanently fixing a cat Whisker upon the most sensitive point of a radio detector crystal, Which consists in mounting the crystal Within one end of a tubular body, then positioning` the end of the cat Whisker upon the sensitive point of the crystal face and connecting said cat Whisker with a conductor, then packing a dry comminuted insulating material Wit in said body against the crystal face and around the end of the cat Whisker to hold the latter against displacement from the sensitive point on the crystal face, and Iinally filling the remaining space Within said tubular body With an insulating material in fluid form to solidify around and upon said conductor and upon a part of the cat Whisker to thereby permanently anchor the same Within said tubular body against movement relative to each other.

In testimony that We' claim the foregoing as our invention, We have signed our` names hereunder.

FREDERICK MICHELS. ADOLPH ERISMAN. 

